Composite materials formed of a fiber matrix plus a resin which may be thermoplastic or thermosetting, for example, are more and more attractive for use in a variety of manufactured goods, e.g. boats, tools, planes, sporting goods, building construction, because their stiffness and strength-to-weight ratios are better than many metals. However, composites are relatively expensive to fabricate especially when they take complex shapes. Fabrication costs can be further increased when there is a need to precisely orient the fibers in a predetermined direction. In one approach dry fiber or fabric is laid up by hand and then the resin is applied and cured. The dry fabric tends to be difficult to keep in position and the more complex the shape the more difficult and time consuming is the layup labor. The fiber can be purchased in pieces (prepreg) already impregnated with the resin which are easier to layup since they are slightly tacky and can be used in complex forming processes but are much more costly than the separate raw materials.
One attempt to use the less expensive raw materials, i.e. separate fiber and resin, and to cut labor costs uses a resin transfer molding machine. While the machine uses the less costly separate fabric and resin, it also requires expensive tooling to contain the fabric during the resin injection step. This tooling is shaped to the particular form desired for the end product composite and requires high volume production runs for amortization. In addition, the process still requires labor-intensive three-dimensional hand layup of the dry fabric in the tooling in preparation for the resin impregnation step. Since the fabric is dry there is added difficulty in laying it up. Fast forming processes which can be used with prepregs, such as press forming or diaphragm forming, may not be used with dry fabrics since they don't retain their shape after forming. In addition it is often difficult to obtain an even impregnation of the fiber with the resin when the fiber is in a complex shape.